1. Field of the Invention.
The invention relates to sheet gauge metal scrap, and to the treatment and processing of such scrap material to facilitate its remelting and re-use in steel making and foundry furnaces. In particular, the invention relates to a process and apparatus in which sheet gauge steel and other metal scrap, produced by stamping and other metal-working operations, is flattened for the purpose of increasing its bulk density to enable it to be transported and used more efficiently in steel-making and foundry furnaces.
2. Description of the Prior Art.
When sheet metal parts are formed in a stamping press, the scrap metal residue is typically bent, deformed, contorted, or distorted in some fashion, so that a piece of flat metal, which is inputted to the stamping process, and has a planar thickness in the range from about 0.012 to about 0.150 inches, is distorted by stamping so that the individual pieces of scrap from the stamping operation have a contortion (or deflection from flatness) of up to about five inches. This scrap has value, and it is desirable to recover this value by converting the scrap to a form in which it can more conveniently and economically be transported and then used as charge for a steel-making or foundary process furnace.
The typical maximum dimensions of the individual pieces of sheet gauge steel or other metal that constitute the scrap which is the feed material for the process of this invention are approximately five feet by five feet, with a contortion of about five inches.
The prior art process for taking this scrap and putting it into a more desirable form for transportation and reprocessing is commonly known as "baling." In the "baling" process, a batch of sheet gauge scrap metal, for example 1,500 pounds, is charged into the so-called baling box of a baling press. In a typical example, the baling box will have a rectangular horizontal cross-section and the walls of the baling box will be rigid. After a batch of sheet gauge scrap metal has been charged into the baling box, hydraulically driven rams compress the charge into a relatively dense cubic "bale" or bundle having dimensions of, for example, two feet by two feed by three feet. This bale or bundle is more easily transportable and usable in remelting operations.
The bales or bundles produced by the prior art have two distinct disadvantages. First, the bales are not as desirable in modern steel-making technology as the loose, flattened, sheet scrap consisting of discrete pieces. Until 1960, the bulk of steel-making was performed in open hearth, furnaces and the scrap charge was designed for such furnaces since the open hearth furnace operated well using bulky scrap pieces in the form of bales or bundles.
Today, however, the open hearth furnace virtually is extinct, and steel-making normally is performed in basic oxygen or electric furnaces. These new furnaces operate more efficiently with a scrap charge made up of relatively small, free-flowing, discrete pieces. This type of scrap results in higher production rates and less damage to furnace linings and electrodes than bulkier scrap such as bales or bundles.
The second disadvantage of the bales or bundles produced by the prior art is that the baling process has much higher costs associated with initial investment, energy consumption, maintenance, and manpower than does the process provided by the Invention.